Heat exchange with explosion gases



Dec. 15, 1936.

H. HOLZWARTH HEAT EXCHANGE WITH EXPLOSION GASES 4 Sheets-Sheetl FiledDec. 2 1, 1953 IIX Sena/v08 M fl M W M T Z R M M w W W m M y B Dec. 15,1936. HQLZWARTH 2,063,928

HEAT EXCHANGE WITH EXPLOSION GASES Filed Dec. 21, 1935 4 Sheets-Sheet 2Dec.'15, 1936. H, HQLZWARTH 2,063,928

HEAT EXCHANGE WITH EXPLOSION GASES Filed Dec. 21, 1933 4 Sheets-Sheet 5disc OM06 m/ VEIVTOR f/mvs //a/. z W/lRT/I 15, 1936. H. HOLZWARTH HEATEXCHANGE WiTH EXPLOSION GASES Filed Dec. 21, 1935 4 Sheets-Sheet 4Patented Dec. 15, 1936 UNITED STATES HEAT EXCHANGE WITH EXPLOSION GASESHans Holzwarth, Dusseldorf, Germany, assignor to Hclzwarth Gas Turbine(30., a corporation of Delaware Application December 21, 1933, SerialNo. 703,465 In Germany December 21, 1932 Claims.

The present invention relates to a process for operating combinedconstant volume explosion chamber and heat exchanger arrangements,especially those including steam generators whereinthe heat exchanger isstruck by high pressure combustion gases generated in the explosionchambers, after which the gases are used for the production ofmechanical energy, a part of the sensible heat contained in the gasesbeing withdrawn therefrom in the heat exchanger prior to the actualutilization of the gases for mechanical purposes.

It is the object of the invention to provide an improved process andapparatus for abstracting heat, for steam generating and superheatingand other purposes, from the live, high temperature, high pressure gasesgenerated by explosion under I constant volume wherein thedisadvantageous effects of the presence of the heat exchanger in thepath of the gases flowing, for example, to a turbine, and resultingprimarily from the enlarged gas space presented by the heat exchangerare reduced to a minimum. The present invention thus provides anarrangement of the type indicated wherein the heat exchanger isadvantageously placed to be swept by gases at practically maximumexplosion temperature and at high velocity, the rate of heat interchangebeing thus high, while a too severe drop in pressure and otherdifficulties of prior arrangements are avoided.

It has already been proposed to operate heat exchangers, such asboilers, with the high pressure gases discharging from constant volumeexplosion chambers, and even to arrange the heat exchanger within theexplosion chamber itself. Both of these methodsfor utilizing the hightemperatures of the explosion gases had however, serious disadvantages.In the first method, wherein the gases were discharged into the heatexchanger and then passed immediately into a turbine, there was aserious fall in pressure which prevented the turbine from utilizingefiiciently the residual energy of the gases; and in the second, dturbances in the course of the combustion resulted, while at the sametime the resistance to the fiow of the gases was increased, and theexchanger was exposed to the destructive influences of the explosionsand the high thermal stresses.

The present invention provides a solution of the problem of utilizingthehigh heat transmitting character of the explosion gases whileeliminating the disadvantages of the prior proposals above described. IThe process according to the invention is characterized essentially bythe fact that the combustible mixture formed in the explosion chamber isexploded while the latter is closed with respect to the heat exchanger,whereupon the explosion chamber and the heat exchanger arranged afterthe same are connected with each other while the gas-filled spaces areotherwise closed on all sides. After the lapse of a definite interval, 5during'which sensible heat is Withdrawn from the gases, the latter aredischarged, preferably into a gas turbine arranged after the heatexchanger. In a further development of the invention, my improved modeof operation can be so modified that the combustion gases are dischargedfrom the heat exchanger after any desired controllable period of actionupon the heat transferring surfaces of the heat exchanger.

The apparatus for carrying out my improved process is characterized bythe feature that both at the explosion gas inlet as well as at theexplosion gas outlet of the heat exchanger arranged after the explosionchamber periodically operated control members or valves are arranged.The control for the member located at the gas inlet of the heatexchanger is so determined that it is opened only after the explosion ofthe mixture confined within the explosion chamber has been substantiallycompleted. The control of the member arranged at the gas outlet of theheat exchanger, on the other hand, is so regulated that it remainsclosed for a certain period of time after the opening of the member atthe explosion gas inlet. 7 The advantages of this new mode of operationare readily apparent. In the first place, the explosion chamber remainsclosed up to the end of the explosion process, and does not have to bealtered in any way from the form determined exclusively by thermodynamicand thermo-technical considerations. The course of the explosion cycleis accordingly undisturbed while a complete combustion or explosion isobtained. On the other hand, there are avoided the undesirably largedrops in pressure caused by the escape of gases out of the heatexchanger during the filling of the exchanger with the high pressuregases flowing out of the explosion chamber after the explosion. The fallin pressure accompanying the 5 filling of the heat exchanger with gasesis kept within comparatively small limits, so that the pressure energywhich remains is still sumciently large to supply the whole compressionwork required for keeping the plant in operation.

The invention will be further explained with the aid of the diagrams onthe accompanying drawings which illustrate also a practical embodimentof the invention. In said drawings,

Fig. 1 shows a pressure-time diagram of the above-described knownprocesses compared with the diagram obtained according to the invention;

Fig. 2 shows a pressure-time diagram according to the process of Fig. 1behind the heat exchanger, that is, directly in advance of the nozzle ofthe turbine wheel arranged after the heat exchanger;

Fig. 3 illustrates the valve-lift diagrams of the control members orvalves;

Fig. 4 shows diagrammatically a structural arrangement embodying theinvention;

Fig. 5 illustrates a pressure-time diagram representing a furtherdevelopment of the inventive idea; while Fig. 6 shows the correspondingvalve lift diagrams;

Fig. 'l is a horizontal section through the distributor along the lineVIIVII of Fig. 4;

Fig. 8 is a vertical section through the distributor on an enlargedscale; and

Fig. 9 represents a horizontal section along the line IX-IX of Fig. 8.

In the diagram shown in Fig. 1, the abscissae indicate time while theordinates represent pressures. The dash line (1 represents the typicalpressure-time diagram of the known constant volume explosion chamber,such as is employed for operating explosion turbines. The ignition ofthe combustible mixture in the explosion chambers occurs at the point I,at which instant the charging pressure prevails in the explosionchamber. By the resulting explosion, the pressure in the explosionchamber rises to the point 2, at which instant the outlet member,usually termed the nozzle valve, is opened, whereupon the high pressurecombustion gases discharge from the explosion chamber. The discharginggases first fill the nozzle channel between the nozzle valve and thesubsequent nozzle. Although this nozzle channel is made comparativelysmall, in view of known thermo-dynamic principles, in the usualexplosion turbines which are now under consideration, yet, because thegases continue during this filling period to escape through the nozzle,there occurs a drop in pressure to the point 3 before equalization ofthe pressures in the explosion chamber and the nozzle channel occurs.From this point 3 on, the regular expansion of the combustion gasesthrough the nozzle begins, the gases being directed by the nozzle intothe turbine, until at the point 4, the charging or scavenging pressureis reached in the explosion chamber. At the instant 4 the next workingcycle begins with the scavenging or charging of the explosion chamber.The curve I-2-3-4 thus indicates the individual process phases of theexplosion cycle between the instant of ignition and the instant ofinitiation of the charging or scavenging.

The dot-dash curve b shows the pressure course in an arrangement inwhich the heat exchanger is connected permanently to the explosionchamber, only the latter, however, receiving fuel to avoid injury to theexchanger by explosion therein. As an increase in pressure occurs in theso limited combustible mixture-filled space, then even during theexplosion, combustion gases flow into the residual gas-filled space ofthe heat exchanger where they compress such residual gases. As a result,only a comparatively low maximum combustion pressure can develop.

This is shown in the pressure line b in wh ch the point 5 indicates themaximum explosion pressure. At the instant 5 the periodically operatednozzle valve, which is arranged in the path of the gases beyond the heatexchanger, is opened and the expansion begins, which at the point 6reaches the charging or scavenging pressure,-

whereupon a new scavenging and charging of the explosion chamber isbegun. The point I indicates the moment of ignition also for the curveb.

By comparing the two diagrams a and b, it will clearly be seen that themaximum pressure of the curve b, represented by the point 5, isconsiderably lower than the maximum pressure, represented by the point2, of the typical pressuretiine diagram of the ordinary constant volumeexplosion chamber.

The first known mode of operation above discussed, in which the heatexchanger is arranged in the path of the gases beyond the controlledoutlet valve of the explosion chamber, is represented in Fig. 1 by thedotted line 0. Here again the normal pressure course occurs up to thepoint 2, and up to such point the pressure line beginning at theignition instant I agrees exactly with the corresponding pressure curveof the diagram a. To show these two curves more clearly upon thedrawings they have been shown as slightly separated between the points Iand 2. The nozzle valve opens at the point 2. However, as the heatexchanger increases enormously the space between the nozzle valve andthe subsequent nozzle which directs the gases to the turbine rotor. andas the gases continue to escape from such channel during the filling ofthis enlarged space, the explosion pressure in the explosion chamberfalls very suddenly and very considerably during this filling process,in fact down to the point I on the dotted curve c, before equalizationof pressure occurs. From the point I on the regular expansion out of thenozzle channel proceeds.

The course of the pressure as indicated by the diagram 0 shows that bythe sudden and considerable fall in the explosion pressure from thepoint 2 to the point I, as contrasted with the other diagrams a and b, aconsiderable reduction in the working area occurs. Such a reduction inthe working area, however, resulting in reduction of the turbine outputbelow the compressor intake, can in no case be permitted if a commercialapparatus is to be obtained.

The continuous line d in Fig. 1 represents the pressure conditions inthe process according to the invention, in which the combustible mixtureis exploded in the explosion chamber while the latter is closed withrespect to the heat exchanger arranged in the discharge path of thegases. After the explosion, the explosion chamber is connected with theheat exchanger, such structures remaining, however, otherwise completelyclosed on all sides. Diagram d representing such process shows first ofall the normal pressure course of the explosion line between the pointsI and 2. At the point 2 the outlet member of the explosion chamber isopened. As now, according to the invention, the explosion chamber andheat exchanger are placed in communication with each other while the gasfilled spaces therein are otherwise completely closed, the pressure dropupon the filling of the heat exchanger. which is closed with respect tothe nozzle, is comparatively small in contrast with the processaccording to the line 0. Pressure equalization between the chamber andthe heat exchanger is reached approximately at the instant 5, whichcorresponds to the maximum explosion pressure of the diagram 1). At theinstant 5, the discharge member in the path of the more toward the line3'4' the less the amountgases behind the heat exchanger is opened; the

expansion line is represented by the course of the line 5-6, whichcorresponds to the expansion line of the diagram b of Fig. 1. 1

The pressure diagrams of the different processes shown in Fig. 1indicate, of course, only the pressure conditions inside of the gasfilled spaces (explosion chamber and heat exchanger). The diagrams show,however, in spite of the fact that they are not real output diagrams,that is, they are not po diagrams, a fairly clear picture of theavailable outputs in the explosion chamber. However, diagrams do notgive a clear picture of the outputs which are available in the turbinearranged in the path of the gases beyond the heat exchanger, that is,immediately in advance of the nozzle. These outputs are illustrated inFig. 2 in which the pressures prevailing in the above-described processimmediately in front of the nozzle of the turbine have beenplotted asordinates.

The dash line a shown in Fig. 2 represents the pressure course 2'-34'immediately in advance of the turbine nozzle in a normal, pure explosionturbine plant corresponding to the diagram I23--4 of Fig. 1. At thepoint 3' the nozzle channel is completely filled with gases at thepressure prevailing in the explosion chamber and from this point theexpansion of the combustion gases proceed to the point 4 exactly asshown between the points 3-4 of Fig. 1.

If that known process, according to Fig. 1, is used in which the heatexchanger is arranged in the path of the gases in advance of the nozzleor outlet valve of the explosion chamber, then there are obtainedpressures in advance of the nozzle as indicated by the-dot and dash lineb in Fig. 2. As according to the mode of representation selected in Fig.1 the outlet member lying in the gas path beyond" the heat exchangenopens at the instant 5 which is later than the instant 2 of the normaldiagram a, the filling line in Fig. 2 in the diagram b also begins laterby the same time interval and in'fact at the instant 9'. In view of thestrong cooling of the combustion gases in the heat exchanger, which isaccompanied by a corresponding reduction in the gas volume and aconsiderable loss inpressure, the result is obtained that the fillingline rising at the point 9 does not reach the point 3 of the diagram atbut ends below the point3', still, however, above the point'5'. Thisfilling line would end at the instant 5 itself if the same arrangementhere under consideration was used but operated with the formation of adividing zone between the incoming air-and the discharging gases,wherein an ignitible mixture formed only in the actual explosion spacesitself, while the combustion gas residue of the preceding explosionremained in the. heat exchanger. In such a mode of operation theexpansion line will be represented by the line 5'--6, while by the usealso of the gas conducting heat exchanger space as additional explosionspace, the expansion line runs somewhat above line 5'-6' but below theline 3'4'. From this consideration it will be evident that the expansionlines obtainable in the known process involving a heat exchangerarranged in the gas path in advance of the outlet member lie between theexpansion lines 5'-6 and 3'-4'. The lines approach the line 5'6 to thedegree in which the heat exchanger remains filled to a greater andgreater extent with the residual gases of the previous explosion; on theother hand, they, approach of heat absorbed by the heat exchanger.

The pressure conditions in advance of the nozzle, according to the knownprocess represented by the diagram 0, in which the heat exchanger isarranged in the gas path beyond the controlled outlet member of" theexplosion chamber in the direction of the nozzle, are repre sented inFig. 2 by the dotted curve 0'. In this case the filling process, inconsequence of the greatly increased nozzle channel volume, runs from2"to I; at the latter instant the expansion begins.

From the above described diagram a, b and a there results, as canclearly be seen in Fig. 2, three working areas of different sizes. Uponcloser observation of these working or output surfaces it will berecognized that the output available atv the nozzle of the turbine inthe lastmentioned process is indicated by the sum of the areas I and II,the area II corresponding to the work which a constant pressure turbinewould deliver. The wedge-shaped area I accordingly represents a gain inoutput over the constant pressure turbine output II. This area LthOW-ever, does not increase the constant pressure output II to such a degreethat the required compressor work could be covered with thelastresulting from the arrangement of the heat exchanger in the gas pathin advance of the control member or nozzle valve of the explosionchamber, while on the other hand the gas turbine output in such processis high enough to cover at least the necessary compressorwork, and whichis represented in Fig. 1 by the full-line diagram |2--3--5-G, isillustrated in Fig. 2 as follows: The outlet member of the explosionchamber in applicant's arrangement, which at the same time representsthe inlet member of the heat exchanger, opens at the point 2', while thegas filled spaces remain otherwise closed, that is, while the outletmember (the true nozzle valve) arranged beyond the heat exchanger in thepath of the gases is closed. Corresponding to the increase in volume bythe gas space of the heat exchanger, the gas pressure in the explosionchamber falls (see curve 2-5 in Fig. 1) At the point 9 of Fig. 2 theoutlet member (nozzle yalve) arranged between the heat interchanger andthe turbine assembly is opened, and there now occurs, corresponding tothe line 9'5', a pressure equalization between the explosion chamber andheat exchanger on the one hand and nozzle channel on the other. At thepoint 5' the expansion line begins, and at the point 6' it reaches theline of the scavenging or charging pressure. It will thus be seen thatthe turbine output according to the invention is represented by the sumof the areas I, II and III. This turbine output is sufficiently large totake care of the whole compressor intake.

As the true explosion chamber in the process according to the inventionis not subjected to any complications of structure and to thedisturbances associated therewith, the efiiciency of the combustion canbe raised to the highest attainable value. In this way it has becomepossible, by virtue oi the present invention, to obtain a good overallefiiciency with an entirely satisfactory arrangement of heat exchangerfrom the combustion-technical standpoint. In connection therewith theadvantage can be realized that the prior normal capacity of the heatexchanger, in view of the unusually high gas velocities and of theresulting high rate of heat interchange, is secured with an extremelysmall heat exchange surface or, conversely, with the usual size of heatexchanger the output can be considerably increased.

It is desired to point out further that the working areas I, II, III andIV of Fig. 2 are not identical with the absolute values of the availableoutputs, but are to be regarded only schematically as output areas. Anexact representation of the proper values of the working and heat areaswould require the aid of entropy diagrams. The latter, however, wouldnot as clearly explain and illustrate either the inventive idea or thestate of the art, as do the pressure-time diagrams shown on thedrawings.

In Fig. 3 are shown the valve lift diagrams of the outlet members whichare controlled one after the other in accordance with the invention. Thecurve III shows the diagram for the outlet member between the explosionchamber and the heat exchanger, while curve II shows the correspondingdiagram of the later opening nozzle valve which is arranged between theheat exchanger. and the subsequent turbine assembly. The first outletmember opens at the point 2" and the second at the instant 9".

Fig. 4 shows by way of example a satisfactory arrangement according tothe invention. The

numeral l2 indicates the explosion chamber which is provided in theusual manner with an inlet member l3 for scavenging and charging air,with a fuel inlet member l4 and an igniting device l5. The heatexchanger l6 comprises a separate compartment arranged in the path ofthe gases behind the explosion chamber l2. In accordance with theinvention, there are arranged periodically controlled valves l9 and 20at the gas inlet I! of the heat exchanger l6 and at the gas outlet 18thereof, respectively. The valve member l9 simultaneously controls theoutlet 2| of the explosion chamber, while the control member 20 isarranged immediately in front of the nozzle 22 of the turbine 23. Thecontrol member 20 is thus to be designated as the true nozzle valve.

To the turbine shaft 24 is coupled the compressor 25 which feeds therequired scavenging and charging air under pressure through the conduit26. Both the charging air valve l3 as well as the outlet members I 9 and20 may advantageously be controlled hydraulically by means of oil underpressure which is brought into action periodically at predeterminedinstants by a rotary distributor 21 of known construction, the oil beingcharged through conduits 28, 29 and 30 and acting upon control pistons3|, 32 and 33 (the last of which is not illustrated) connected with therespective control or valve members. The heat exchanger I6 consists of atubular coil 34 connected on the one hand with the cooling space 36 ofthe explosion chamber through the curved goose-neck connection 35, andwith the cooling spaces 38 and 39 through the similar connection 31. Thecooling agent is conducted to the cooling space 36 of the explosionchamber under high pressure by the pump 40 and is withdrawn in highlyheated condition from the cooling space 39 by the conduit 4| After beingpartially decompressed in the reducing valve 42 the heated cooling agentflows to a steam separator 43 in which the generated steam underpressure is withdrawn at 44, while the un vaporized cooling agent isreturned by conduit 45 to the pump 40 and by the conduit 46 to thecooling space 36 of the explosion chamber. The cooling Water withdrawnfrom the cooling water circuit in the form of steam is replaced withfresh feed water by the pump 40a.

According to the invention, the valves l9 and 20 are so controlled, asindicated in Fig. 3, that the mode of operation represented by the solidlines in Figs. 1 and 2 takes place. There are obtained in this way thenovel effects which have been described above with the aid of thesefigures.

In a further development of the invention, the improved mode ofoperation can be so carried out that the duration of the action of thecombustion gases on the heat transferring surfaces of the heat exchangeris regulated in a definte manner. In this way it is possible, uponchange of the load conditions on the gas turbine and on the heatexchanger located in the path of the gases, always to adjust the outputof the exchanger in proper degree to the amount of heat receivingmedium, (for example, steam) required at any time. This development isbased upon the recognition that certain cases exist in which the outputof the heat exchanger and that of the gas turbine vary with respect toeach other, as when the need for steam from the heat exchanger or theload on the gas turbine is subject to rather large fluctuations.Conversely, there are cases in which the steam requirement remainspractically unchanged while the load on the gas turbine, or on any otherenergy consuming machine, varies greatly at certain times. This will bethe case, for example, when the machine driven by the combustion gasesoperates a current generator, as indicated at 53 in Fig. 4, whosenetwork is subjected to varying loads due to the irregular demand forpower, particularly by the cutting in or cutting out of certainelectrically driven machines and devices.

It is advantageous to combine the load changes of the above mentionedaggregates with a suitable regulation of the output of the explosionchamber or chambers by changing the load conditions in such manner thatthe output of the ex-' plosion chamber is alway fitted in correct degreeto the load condition of the said aggregates at any moment. However, theheat content of the generated gases changes with a change in the outputof the explosion chambers. As is known, the heat content of the highpressure combustion gases, together with other factors, is controllingfor the heat transfer to the heat transmitting surfaces of the heatexchanger, and it will also be clear that with every change in theoutput of theexplosion chambers there will occur also a change in theamount of heat transmitted in the heat exchanger. If, corresponding tothe known mode of operation, the duration of the action or contact ofthe explosion gases upon the heat transferring surfaces of the heatexchanger remains practically uninfiuenced by the change in output ofthe explosion chambers themselves, that is, such duration is maintainedat an initially adjusted value, the output of the heat exchanger doesnot correspond to the actual requirements. In order to fit the output ofthe heat exchanger correctly to the steam requirement at any time, theduration of action of the combustion gases upon the heat transmittingsurfaces of the heat exchanger is suitably altered, according to theinvention, upon change in the relative magnitudes of the loads on theheat exchanger and on the gas-operated machine (e. g. turbine). Inconsequence there is efiected an increase in the time of action of thegases upon increase in the load on the heat exchanger, and in thereverse case this time is reduced. If, on the other hand, only thegasdriven mechanism, such as a gas turbine arranged in the gas pathfollowing the heat exchanger, is subjected to changes in the load, whilethe output of the heat exchanger is to be maintained constant, then alsoin this case the duration of the action of the gases must be regulatedsince, as already mentioned, a change in the amount of heat generated bythe explosion accompanies a change in the output of the explosionchambers effected by regulation of the feed supply in known manner. Inorder to maintain constant the quantity of heat to be transferred in theheat exchanger in such case, it is necessary either to reduce the timeof action of the gases upon the heat exchanger upon increase in theirheat content, or to increase such time of action upon reduction of theheat content.

For carrying out the above described process, there is employed acontrol for the closure member located in the gas path beyond the heatexchanger (i. e., the outlet member 20 in Fig. 4) which opens thismember in dependence upon the moment defining the termination of theperiod of action of the gases upon the heat transferring surfaces of theheat exchanger. The conditions involved in such control arediagrammatically presented in Figs. and 6. The diagram shown in Fig. 5repeats in the curve l-2-5--6 the full line diagram d of Fig. 1representing the basic process of the invention, according to which theignition of the combustible charge in the explosion chamber occurs atthe instant I. At the instant 2, in which the maximum pressure isobtained in the explosion chamber l2, the outlet member I9 is opened. Inthe valve lift diagram of Fig. 6, this instant corresponds to the point2". It indicates the initial point for the lift diagram of the outletmember l9 represented by the light line H]. The explosion gases escapingfrom the explosion chamber then fill the heat exchanger 16, whose outletis closed, until at approximately the instant 5 the pressures in the gasfilled spaces of both the heat exchanger and the explosion chamber isequalized. In accordance with the further development of the invention,the expan-' sion line does not, as in Fig. 1, begin at the instant 5,such expansion line of Fig. 1 being indicated in Fig 5 by the dottedline running to point 6, but such expansion beginslater by the variabletime interval :13. The expansion xx thus begins at the point 5a. In thevalve diagram of Fig. 6, this point corresponds to the point 9 at whichthe lift diagram Illa of the outlet member 20 of the heat exchangerbegins.- The expansion continues from the point 5a to the point 6a,approxi-' mately when the scavenging or charging pressure is reached inthe explosion chamber.- Because of the fact that whenthe opening of theoutlet 20 of the heat exchanger is delayed by the variable time intervala: after pressure equalization has been reached in the gas filled spacesof the heat exchanger and explosion chamber, the combustion gases actfor a correspondingly longer time upon the heat transferring surfaces.vTo a degree depending upon the length of the interval :c,a

greater amount of heat will be withdrawn from the gases than is the-casewhen the expansion I line begins at the instant 5 or at the instant 2.As the quantity of heat generated in the heat exchanger, other factors,particularly the co-efiicient of heat transfer, remaining the same, isdependent upon the duration of the action of the gases, the presentinvention makes it possible, by proper measurement of the arbitrarilyvariable time of action of the gases upon the heat exchanger surfaces,accomplished by the shifting of the instant 5a and of the valve openinginstant' 5", to regulate exactly the amount of heat absorbed in the heatexchanger. In this way the amount of heat transmitted to the heatexchanger can be fitted in an economical way to the amount of heatedmedium (steam or hot water) required at the place of use.

If in the explosion turbine plant shown in Fig. 4 the process is one inwhich the load on the explosion turbine 23 operated by the gasesdischarged by the outlet member 20 of the heat exchanger l6, issubstantially constant, while the consumption of steam (or hot water)produced in the heat exchanger l6 varies, for example falls,

then the stay or the period of action of the combustion gases in theheat exchanger, that is, the interval :0, is correspondingly reduced,and the charging conditions of the explosion chamber l2 are likewisechanged, in so far as the latter measure is necessary to keep the outputof the gas turbine 23 constant. In the reverse case, that is, uponincrease in the steam requirement, the interval at, and thus the-periodof heating by the combustion gases, is increased. The heating period ofthe combustion gases required at any time is adjusted by advancing orretarding the moment of opening of the outlet member 20 of the heatexchanger l6.

The explosion plant of Fig. 4 can also be'operated in such manner thatthe load on gas turbine 23 falls while the consumption of steamgenerated in the heat exchanger remains substantially constant. If theload on the gas turbine changes, the output of the explosion chamber isadjusted to the load conditions at any time. This results necessarily ina simultaneous change in the charging conditions of the explosionchamber. The change in the charging conditions, as already explained, isaccompanied by a change in the heat content. of the combustion gases. Inorder to avoid irregularities in the output of the heat exchanger, theperiod of action of the combustion gases is reduced or increased toproduce a constant generation of steam.

In order to avoid harmful reactions, particularly pre-ignitions when thewall temperatures of the explosion space become very hot, upon themixture which is to be ignited at a predetermined instant or' upon thecomponents of the mixture, it is necessary to regulate the quantities ofheat acting upon such mixture. Ordinarily there is retained in theexplosion chamber a certain amount of residual gases from the precedingexplosion by premature closing of the outlet member. The sensible heatcontained in such gases acts upon the components of the mixture toprepare or prime the same. As the wall temperatures of the explosionchamber assist in priming the mixture by radiation of heat thereforexample, by varying the displacement or scavenging process of theresidual gases remaining from the preceding explosion. The change in thescavenging process can occur in a variety of ways, as has already beenproposed in a known method of operation. The regulation of the quantityof heat acting upon the mixture has proved to be particularlyadvantageous when the narrowest discharge cross section, which iscontrolling for the displacement of the residual gases, is varied duringthe process. However, simultaneously with such change, or separately,the duration of the residual gas displacement can be regulated. Theregulation of both of these factors is associated with a change in thequantity of residual gases trapped in the explosion chamber, and thuswith the scavenging of the chamber. If now the wall temperature of theexplosion space is very high, then in accordance with these proposalsthe undesired excessive influence of the heat upon the mixture can beprevented by a more vigorous scavenging, the amount of residual gasesleft in the explosion chamber being reduced either by exposing largeroutlet cross sections or by increasing the scavenging period or byadopting both measures. The outlet cross-sections may be regulated asdisclosed in my Patent No. 1,756,139; while the duration and hence thede gree of scavenging can be controlled in the manner described in myPatent No. 2,003,292.

It will be noted that the heat exchanger compartment is small ascompared with the explosion chamber; in fact, the free space in the heatexchanger should be made as small as possible consistent with efficientheat transfer in order to reduce the pressure drop attending theequalization of the pressures in the explosion chamber and heatexchanger Fig. '7 represents that part of the distributor which controlsthe piston 32 of the nozzle valve l9 through pipe line 29. Thestationary housing is designated by the number 21a, the rotary part by21b. The space 41 is connected with the interior of the rotary part 211)and thus with the oil pump 49 through the pipe 50 (of Fig. 4), the space48 with a drain leading to the space 5| (of Fig. 4) of the distributor.During rotation of the rotary part 21b, therefore, pressure oil isalternately admitted or released from the piston 32 (of Fig. 4) openingand closing the nozzle valve [9 accordingly.

Figures 8 and 9 show constructions which allow for varying the moment ofaction for the control members 13, 20 or the hydraulically operated fuelpump 52 (of Fig. 4). Around the rotary part 2117 are arranged movablesleeves 53, 54, and 55. By turning said sleeves the moment of actuatingthe corresponding mechanical devices is changed as shown for the sleeve53 in Fig. 9. The sleeve 53 is provided with a slot 56 which furnishesthe controlling edges for admitting or releasing the pressure medium toor from the pipe 30. As soon as the sleeve 53 and therewith the slot 56is moved by means of the spiral gears 51 and 58 and the hand wheel 59 ina di rection against the direction of rotation of the rotary part 21bthe piston 33 of the valve 20 is actuated earlier, and as soon as thesleeve 53 is moved in the opposite direction the valve 20 is actuatedlater. In this way the opening of the valve 20 may be varied as comparedto the opening of the valve l9. In the same way the scavenging periodmay be influenced by turning the sleeve 54, thus changing the moment ofopening or closing the valve I3, while the admission of the fuel may bevaried accordingly by shifting the sleeve 55.

I claim:

1. The combination of a constant volume explosion chamber, a heatexchanger connected with said chamber .and arranged in the path of thegases discharging from such chamber, a control member at the inlet ofthe heat exchanger, a

second control member at the outlet of the heat exchanger, and means fortiming the opening and closing of said control members in sequence toregulate the time interval during which the explosion gases remain underhigh pressure in the heat exchanger before they are discharged by thesecond control member.

2. The combination as set forth in claim 1, wherein said timing means isconstructed to open the first control member only after the combustionof the explosive mixture in the explosion chamber has been substantiallycompleted.

3. The combination as set forth in claim 1, wherein said timing means isconstructed to open first the control member at the inlet of the heatexchanger, the control member at the outlet remaining closed, and thento open the second control member after a selected time interval duringwhich the pressure in the explosion chamber and heat exchanger hasbecome substantially uniform.

4. The combination as set forth in claim 1,

wherein the timing means is constructed to open the control member atthe outlet of the heat exchanger at the end of a predetermined intervalafter the opening of the control member at the inlet of the heatexchanger to enable the gases to exert a predetermined heating effect inthe heat exchanger.

5. Apparatus according to claim 1, including a combustion gas turbinearranged to receive and be driven by the gases discharged under pressureby the control member at the outlet of the heat exchanger.

HANS HOLZWARTH.

